282 Eue Warming. 



quick expansive. In all Arctic Caryophyllaceæ it will certainly 

 be found that the youngest leaves are, during the winter, 

 protected by older leaves, which are more or less withered. 

 That the peculiar condition of the protoplasm, and the 

 different substances contained in the cells, can protect 

 against the cold of the various seasons, must be taken for 

 granted. With regard to this, however, I cannot give any 

 new information. 



IV. Flower-biology and Notes on Seed-production. 



In by far the greater majority of the Arctic-flowering 

 plants it appears that the flowers are formed during the 

 year previous to that in which they open, and that they 

 pass the winter in a more or less well-developed condition, 

 — a circumstance which is a natural adaptation to the ex- 

 treme brevity of the favourable season of the year (the 

 extreme brevity of the summer-time). 



In the foregoing papers in "Meddelelser om Grönland" 

 belonging to this series, the fact that the flowers are formed 

 during the year previous to that in which they open, has 

 been specially pointed out in a number of species by Knud 

 Jessen (Ranunculaceæ, Rosaceæ) and others, and for in- 

 stance, as regards the CaryophyUacese, this is found to be 

 the case in Cerastium alpinum in Iceland and the Færoes 

 (Helgi Jonsson), Silène acaulis (idem), Cerastium trigynum 

 in Norway (Th. Resvoll), Melandrium apetalum (eadem), and 

 Minuartia biflora. On Greenland material, gathered on 

 Aug.6th, I found buds which enclosed flowers for the next year. 



As an example I give here (Figs. 25) some figs, of Silène 

 acaulis. The material was gathered by C. Ryder near Uper- 

 nivik on ground which had recently been bared of snow. 

 The buds which were present had evidently passed through 

 the winter. The buds were 1/ 2 mm in transverse section; 



